Final answer:
The distance between ship A and ship B is changing at approximately 75.714 km/h at 4:00 p.m. This was determined by using the Pythagorean theorem to calculate the distance between the two ships as they move, and differentiating it with respect to time.
Step-by-step explanation:
To determine how fast the distance between the two ships is changing at 4:00 p.m., we can use the Pythagorean Theorem to represent the distance between them.
Let ship A have moved x km east from its original position after t hours, while ship B has moved y km north from its original position after t hours. At noon, the ships were 170 km apart, so when t = 0, x = 0 and y = 0.
Ship A's speed is 40 km/h east, and ship B's speed is 35 km/h north, so:
The distance d between the ships at any time t is given by:
d(t) = √((170 - x(t))^2 + y(t)^2) = √((170 - 40t)^2 + (35t)^2)
To find the rate at which distance d is changing with respect to time t, we need to differentiate d with respect to t:
Ωd/dt = (1/2) * [2*(170 - 40t)*(-40) + 2*(35t)*(35)] / √((170 - 40t)^2 + (35t)^2)
At 4:00 p.m., which is 4 hours after noon, we substitute t = 4 into the derivative to find the rate at which the distance is changing:
Ωd/dt at t = 4 = (1/2) * [-2*10*(-40) + 2*140*(35)] / √((10)^2 + (140)^2)
Ωd/dt at t = 4 = [800 + 9800] / √(19600)
Ωd/dt at t = 4 ≈ 10600 / 140 ≈ 75.714 km/h
The distance between the ships is changing at approximately 75.714 km/h at 4:00 p.m.